Staple gun



FIG. 1 is a perspective view of a staple gun showing my new design;

FIG. 2 is a side view thereof;

FIG. 3 is a bottom view thereof;

FIG. 4 is the opposite side view of FIG. 2 thereof;

FIG. 5 is a top view thereof;

FIG. 6 is a front view thereof; and,

FIG. 7 is a rear view thereof.

The ornamental design for a staple gun, as shown and described.